In Fig. REF , the message with 256 bytes has higher reliability and lower latency than long one (i.e., with 512 or 1024 bytes). To achieve high reliability (over \(99.99\%\) ), the 512-byte message can be framed into packets by using 6000 channel uses, as shown in Fig. REF (a), but its latency is about 18s, as shown in Fig. REF (b), which exceeds the maximum latency budget for URLLC applications [1]}. The 1024-byte message is transmitted with the latency of 20s and reliability of \(90\%\)  at 6000 channel uses, which does not meet the stringent requirements of latency and reliability. Thus, the long-messages are not able to support URLLCs in IoT networks and low-latency transmission in factory automation.
